1. Field of the Invention
This invention relates to controlled lock apparatus for barred windows and, in particular, to such apparatus for automatically unlocking window bars in response to a smoke detector.
2. Description of the Related Art
The increasing prevalence of crimes against property has led to the widespread use of window bars on dwellings and other buildings to prevent unauthorized entry through the windows. When bars are permanently mounted on a window without provision for their quick removal or release from the inside, they prevent emergency egress through the window in case of fire in the interior of the building. They also keep firemen and others from effecting the rescue of persons trapped within. Because of many tragic deaths resulting from people being trapped inside buildings with bars on the outside of the windows, various laws and building regulations have been passed in many jurisdictions which require that exterior window bars be unlockable from the interior of the building to which they are attached.
Unlockable window bar arrangements at present still take time to operate so that an occupant of the building can escape through the window in the event of a fire, sometimes requiring that a key be located to unlock the window bars. Since the confusion engendered by smoke and heat associated with a fire can cause even relatively simple tasks to assume the proportions of great difficulty, it would be a great boon to the field of fire safety if there were some means of automatically unlocking window bars in response to a fire in its early stages. An automatic unlocking apparatus for window bars would undoubtedly save many lives that are currently being lost in fires due to panic or clouded judgment under the stressful conditions of a life-threatening emergency.
Smoke alarms are now generally required by law in dwellings. Although some local ordinances require the smoke detectors to be wired to AC line current, a power failure can render them inoperative, and in some cases the power failure is a result of the fire itself. Battery-operated smoke detectors must be periodically checked to insure that the batteries have adequate potential to operate the detector. Neither hard-wired nor battery-operated smoke detectors offer a fail-safe method of warning the occupants of a building in case of fire. It would be an additional great benefit to the field of fire safety if there were available some way of powering smoke detectors that was fail-safe against power failure or battery discharge.
From the above discussion it can be seen that it would be an extremely beneficial advance in the field of fire safety if there were available a window bar locking arrangement which could be automatically unlocked by means of an apparatus which detected a fire in its early stages and at the same time provided a fail-safe power supply for the fire detection device.